JP3902577B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus, and more particularly to a positioning structure for an openable / closable structure used in the apparatus.

  In the electrophotographic copying method, which is one of the image forming methods, a latent image corresponding to a document is formed on a photoconductor, and the latent image is processed with a visible image with toner and transferred to a transfer material such as plain paper. The transferred toner image is fixed to obtain a copy. Examples of the apparatus using such an electrophotographic copying system include a copying machine, a printer, and a facsimile machine.

  In an image forming apparatus, a structure that constitutes the apparatus when a transfer material onto which a toner image is transferred from a photoreceptor is clogged in a conveyance path or when toner used in a developing process for obtaining a toner image is replenished. Some have a structure in which the body is divided into two so that one of the structures can be opened and closed, and the inside can be exposed when opened.

  An image forming apparatus having a structure divided into two parts has a structure in which each structure is positioned at a predetermined position so that one of the structures is not inadvertently opened when the structure divided into two parts is closed. Has been proposed (for example, Patent Documents 1 to 3).

  In Patent Document 1, one of the openable and closable structures is supported so as to be opened and closed by inserting the open / close fulcrum shaft into the elongated hole of the other structure, and the one structure is supported with respect to the other structure. When closed, a configuration is disclosed in which the rotation shaft of the gear positioned at the open / close end of one structure is fitted in a groove formed in the other structure and the rotation shaft of the gear is held by a hook. ing.

  Patent Documents 2 and 3 show a structure in which the other structure is detachably supported with respect to one structure, although it is not opened and closed, and is formed on the side plate of one structure when mounted. The groove formed in the other structure is fitted to the rotating shaft of the roller forming one of the conveying members, and the hook having the state in one structure is formed on the other structure. A configuration is disclosed that is held by engaging with a portion.

Japanese Utility Model Publication No. 5-6973 Japanese Patent Laid-Open No. 1-133822 Japanese Patent Laid-Open No. 1-133823

  There is a case where a fixing device for fixing a toner image is disposed on one of the divided structures. When the fixing device is disposed on one of the openable structures, the developing device is disposed below the fixing device, and the development is performed by opening one of the structures to expose the inside. This is because toner can be supplied to the apparatus.

  The fixing device arranged on one side of the structure is provided with a roller pair combining a heating roller and a pressure roller for fixing the toner image while also conveying the transfer material. The driving force is transmitted through a transmission member such as a gear.

Since the transmission member provided in the roller pair is attached to one axial end of the roller, the load at the axial end of the roller is different. In this case, a distinction is made between the end where the meshing reaction force from the gear acts and the end where it does not. For this reason, the axis of the roller may be inclined without being parallel to the axis of the other transport rollers.
When the directions of the axes of the rollers that are conveying members arranged in the conveying path of the transfer material are not parallel, the direction in which the transfer material nipped and conveyed between the conveying members is changed, A phenomenon occurs in which wrinkles occur in the width direction of the transfer material or the transfer position of the toner image is tilted with respect to the moving direction of the transfer material. In addition, when the axes are not parallel, the distance between the transmission members also changes, which causes the meshing between the transmission members to become unstable, or one of the idling phenomena of the gears. A certain tooth skipping phenomenon occurs.

  The fixing device arranged on one side of the structure opens and closes with respect to the other structure together with one of the structures, and is fixed because it is covered and fixed to the other structure when closed. It may be used to hold the position of the image forming processing device located below the fixing device. For example, in the case where a charging device that performs the charging process of the photosensitive member is disposed near the lower portion of the fixing device, the charging device is configured by pressing an upper surface of the charging device with an elastic body interposed between the charging device and the upper surface of the charging device. There is a configuration for maintaining the position of In this case, since the reaction force of the elastic body acts in the direction of pushing up the fixing device, the conveying path length between the position of the roller pair in the fixing device and the other conveying rollers tends to increase. There are things to do. As a result, the clamping timing of the transfer material by the roller pair is out of order, and the leading edge of the transfer material fed from the other transport rollers may hang down before reaching the roller pair of the fixing device, which may cause a jam. is there. Such a phenomenon often occurs not only due to the above-described load difference in the axial direction of the roller, but also due to a processing error in the structure supporting the scraped member. When correcting the inclination of the axis of the rollers, for example, it may be necessary to check the positioning state of each roller one by one, which requires a complicated procedure of checking the positioning state in addition to the opening / closing operation of the structure. Become.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a conventional image forming apparatus, and more particularly, to an image forming apparatus having a configuration capable of accurately performing positioning of a structure that occurs when an openable / closable or detachable structure is combined. Is to provide. In particular, when the structure in which the fixing device is arranged is one structure and the image forming apparatus main body is the other structure, the structure can be positioned accurately. Another object of the present invention is to provide an image forming apparatus having a configuration capable of preventing the occurrence of wrinkles on the transfer material and the inclination of the image.

The invention according to claim 1 includes a first and second structures divided into two, and a pair of rollers forming a conveying member is provided on the first structure that is supported by the second structure so as to be opened and closed. An image forming apparatus having a configuration in which a fixing device having the first structure is disposed, wherein the first structure is provided when the first structure is closed so as to be rotatable with respect to the second structure. a first holding means capable of locking the body, fitting into the second structure when the provided rotatably relative to the first structure to the first structure is closed Second holding means that can be provided, and the first holding means has a pressing portion provided at a part thereof so as to face the second holding means when the first structure is closed. By being pressed by the second holding means, the first structure is rotated in the locking direction. The second holding means is configured to be rotated in a direction to release the locking of the first structure in conjunction with the release of the fitting with the second structure. It is characterized by being configured.

According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the first holding unit corresponds to the open / close end side of the first structure body having a large radius from the open / close fulcrum. The second holding means is provided in the first structure body corresponding to the opening / closing base end having a small radius from the opening / closing fulcrum in the first structure body. Yes.

  According to a third aspect of the present invention, in addition to the first aspect of the invention, the second holding means has a fitting portion with respect to the second structure in one longitudinal direction around the swing support shaft, and the longitudinal direction. On the other hand, there are respectively provided operation portions that are rotated by an operator, and the first holding means is separated from the locking portion for the first structure by the fitting portion in the second holding means. A pressing portion that presses the locking portion with the first structure in the locking direction, and a push-back portion that is pushed back in the direction opposite to the locking direction are provided, and the fitting portion in the second holding means Acts on either the pressing part or the push-back part, thereby locking and unlocking the first structure.

  According to the first and third aspects of the invention, a part of the first holding means faces the second holding means, and is pressed by the second holding means when the first structure is closed. A structure for releasing the locking of the first structure in conjunction with the state in which the first structure is locked and the second holding means being released from the fitting with the second structure. Therefore, the second holding means can more reliably lock the first structure by the first holding means, and the first holding means can be unlocked by the second holding means. Is possible.

According to a second aspect of the present invention, the first holding means is provided in the other structure body in correspondence with the opening / closing end side having a large radius from the opening / closing fulcrum in the first structure body. Since the holding means 2 is provided in the first structure corresponding to the opening / closing base end having a small radius from the opening / closing fulcrum in the first structure body, from the opening / closing base end side of the first structure body the inclination of reliably engaging to the roller axis substantially the entire leading to the opening and closing end side is prevented from occurring becomes possible.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

FIG. 1 is a view showing a copying machine as one of image forming apparatuses according to an embodiment of the present invention. In FIG. 1, the copying machine 1 includes two divided structures 2 and 3 (hereinafter, for convenience, 1 and 2), and the first structure 2 is an apparatus main body (hereinafter referred to as an apparatus main body 3) forming the second structure 3 as shown in FIG. 2. On the other hand, it is supported to be freely opened and closed through a hinge portion H serving as an opening and closing fulcrum.
Inside the apparatus main body 3, a drum-shaped photosensitive member (hereinafter referred to as a photosensitive drum) 4 is disposed as a latent image carrier, and an image is formed around the photosensitive drum 4 with respect to the photosensitive drum 4. A charging device 5, an image writing device 6, a developing device 7, and a transfer device 8 for performing a forming process are arranged.
A paper feeding device 9 that can be inserted into and removed from the device main body 3 is disposed below the device main body 3, and a paper discharge table 10 that accommodates a transfer material S carrying a toner image is disposed on the upper surface of the device main body 3. Has been placed.

  The photosensitive drum 4 can be rotated in the direction of the arrow shown in the drawing. In the rotation process, the charging device 5 performs uniform charging, the image writing device 6 performs exposure, the developing device 7 forms a toner image, and the transfer device 8 performs The transfer of the toner image onto the transfer material S is performed. The toner image electrostatically transferred to the transfer material S by the transfer device 8 is fixed by the fixing device 11.

  The fixing device 11 includes a housing 12 fixed to one structure constituting the copying machine 1, that is, the first structure 2, and a heating roller 13 and a pressure are provided inside the housing 12. A roller pair comprising a roller 14 is provided.

  In FIG. 2, the housing 12 has an opening / closing end at a position where the radius from the hinge portion H (see FIG. 2) serving as the opening / closing fulcrum of the first structure 2 is large, and a position where the radius from the hinge portion H is small. It is the open / close base end.

  The roller pair has a function of heating and fixing the toner image carried on the transfer material S and conveying the transfer material S. For this reason, the heating roller 13 and the pressure roller 14 constituting the roller pair are It is supported so that it can rotate in contact with each other. The roller pair is disposed at a position where the transfer material S that is nipped and fed between the photosensitive drum 4 and the transfer roller in the transfer device 8 can be nipped and conveyed, and the position is defined by a holding unit that will be described later. .

  FIG. 3 is a view for explaining the structure of the holding means which is a precondition for use in the image forming apparatus according to the embodiment of the present invention. In the figure, the holding means locks two portions of the housing 12. The first holding means 16 provided on the side wall 3a of the apparatus main body 3 corresponding to the open / close end side of the housing 12 and the housing 12 corresponding to the open / close base end side of the housing 12 are provided. The second holding means 17 is provided.

  The first holding means 16 is composed of a swingable sheet metal member whose base end is supported by a support pin 18, and has a bent piece 16a at the swing end, and the top of the bent piece 16a. Is formed with a raised piece 16b bent upward. An elastic body 19 that urges the first holding means 16 in the clockwise direction in FIG. 3 is disposed at the swinging end of the first holding means 16.

  The first holding means 16 is slid against a stopper (not shown) provided on the side wall 3a of the apparatus body 3 by the urging of the elastic body 19, whereby the amount of clockwise swing is defined, and the rising piece The state in which 16b faces in a substantially vertical direction is the normal state. This normal state corresponds to a state in which the housing 12 can be locked when the first structure 2 is closed.

  The second holding means 17 is constituted by a sheet metal locking claw that is rotatably supported by a support shaft 20 inserted through a support portion 12 a provided on the lower surface of the housing 12. When the first structure 2 is closed, the support shaft 20 is fitted into and supported by the recess 3b formed in the side wall 3a of the apparatus main body 3. The recess 3b is used to define the position of the housing 12 when the structure 2 is closed.

The second holding means 17 is urged counterclockwise in FIG. 3 by a helical spring (not shown).
The second holding means 17 is provided with a claw portion 17a at one end in the longitudinal direction around the support shaft 20, and an operation portion 17b at the other end in the longitudinal direction.

  As shown in FIG. 4, the operation portion 17 b is configured by a lever that extends upward from the housing 12. The operating portion 17b is inserted into a guide groove (not shown) and protrudes above the housing 12, and is restricted by the guide groove to restrict the rotation amount of the second holding means 17. 4 and the subsequent drawings mainly show the configuration of the roller pair, the housing 12, and the first and second holding means 16 and 17 included in the fixing device 11, and the fixing device 11 includes the conveyance guide and the like. The other members are omitted.

A locking piece 12b is formed on the side bottom of the housing 12 corresponding to the first holding means 16 so as to project toward the bent piece 16a of the first holding means 16.
The size of the contact surface of the locking piece 12b with the bent piece 16a (corresponding to the length of the range indicated by L in FIG. 3) is locked on the upper surface by the bent piece 16a. When the structure 2 is opened, the size is set so as to be easily detached from the bent piece 16a while swinging the first holding means 16.

  On the side wall 3a of the apparatus body 3 corresponding to the second holding means 17, an engaging member 21 having a protrusion 21a that can be engaged with the claw portion 17a is integrally formed.

  The operation of the above configuration is as shown in FIG.

FIG. 5A shows a state where the structure 2 is completely closed. In this state, the closed position of the first structure 2 is defined by the apparatus body 3 (only the side wall 3a is shown in the figure).
When the first structure 2 is completely closed, the locking piece 12b of the housing 12 enters and engages with the lower surface of the bent piece 16a of the first holding means 16 to be pressed, and the second holding means. The 17 claw portions 17 a engage with the protrusions 21 a of the engaging member 21 of the apparatus main body 3. As a result, the fixing device 11 is positioned by locking the opening / closing end side of the housing 12 by the first holding means 16 and the opening / closing base end side of the housing 12 by the second holding means 17. The position of the roller pair is set to a predetermined positional relationship with respect to the facing position between the photosensitive drum 4 (see FIG. 1) and the transfer roller included in the transfer device 8 (see FIG. 1).

  FIG. 5B shows a state in which the first structure 2 is being closed toward the apparatus main body 3, and in this case, the engagement of the housing 12 is interlocked with the first structure 2 being closed. The stop piece 12b moves toward the raising piece 16b of the first holding means 16 as indicated by an arrow in the drawing.

  As shown in FIG. 6, when the first structure 2 approaches a state where it is completely closed, the locking piece 12 b of the housing 12 abuts on the rising piece 16 b of the first holding means 16, and the elastic body 19. The first holding means 16 is swung counterclockwise in the figure against the urging force, so that the locking piece 12b of the housing 12 enters the lower surface of the bent piece 16a of the first holding means 16. The protrusion 21a of the engaging member 21 that the claw portion 17a of the second holding means 17 has on the side wall 3a of the apparatus main body 3 in accordance with the engagement of the first holding means 16 and the locking piece 12b of the housing 12. Engage with. As a result, the state shown in FIG.

  When the first structure 2 is opened in a direction away from the apparatus main body 3, the second holding unit 17 causes the claw portion 17 a to be engaged with the engaging member 21 by the operation portion 17 b being operated by the operator. Separated from the protrusion 21a. As a result, the restraint of the housing 12 by the second holding means 17 is released. Therefore, when the housing 12 is interlocked with the movement of the first structure 2, the locking piece 12 b of the housing 12 is attached to the first holding means 16. It can detach | leave from the bending piece 16a.

  In the configuration as described above, a part of the housing 12 can be used as a part of the holding mechanism for positioning, so that the structure required for positioning can be simplified. In addition, since the rollers of the pair of rollers constituting the transfer material conveying member are installed in the housing 12 in advance, it is not necessary to adjust the contact force between the rollers as compared with the case where the rollers are individually positioned, and the positioning operation is performed. Becomes easier.

  In the above embodiment, as shown in FIG. 1, the fixing device 11 is used, and the elastic body P is arranged at the bottom of the housing 12 in order to hold the position of the charging device 5 located in the vicinity thereof. Is also possible.

Next, an embodiment of the present invention will be described with reference to FIG.
The embodiment shown in FIG. 7 is characterized in that the first holding means shown in FIG. 3 can be interlocked with the second holding means. Of the members shown in FIG. 7, the same constituent members as those shown in FIG. 3 are denoted by the same reference numerals. In FIG. 7, only a part of the operation portion 17b included in the second holding means 17 shown in FIG. 4 is shown.
In FIG. 7A, the first holding means 30 is L-shaped in a side view, and includes a bent piece 30a and a raised piece 30b as in the example shown in FIG. Apart from the one part, a pressing piece 30c facing the lower surface of the claw part 17a of the second holding means 17 and a push-back piece 30d facing the upper surface of the claw part 17a are provided.
The oscillating end of the first holding means 30 is shifted by about 90 ° around the support pin 18 with respect to the oscillating end provided with the bent piece 30a and the raised piece 30b, and the pressing piece 30c. Further, the push-back piece 30 d faces the second holding means 17.

Since the present embodiment is configured as described above, its operation will be described as follows.
FIG. 7A shows a state in which the first structure 2 is completely closed. In this state, the locking piece 12b of the housing 12 is pressed by the bent piece 30a of the first holding means 30, and the claw portion of the second holding means 17 is the protrusion 21a of the engaging member 21 of the apparatus main body 3. Is fitted. The claw portion head portion of the second holding means 17 presses the pressing piece 30 c of the first holding means 30. As a result, the fixing device 11 having the housing 12 is locked at two locations by the first holding means 30 on the opening / closing end side of the housing 12 and by the second holding means 17 on the opening / closing base end side of the housing 12. Therefore, the position of the roller pair is set to a predetermined positional relationship with respect to the opposing position between the photosensitive drum 4 (see FIG. 1) and the transfer roller in the transfer device 8 (see FIG. 1). Moreover, since the pressing piece 30c of the first holding means 30 is pressed downward in FIG. 7A by the pressing operation corresponding to the swing of the claw head portion of the second holding means 17, the first The holding means 30 can press the locking piece 12 b of the housing 12 in conjunction with the movement of the second holding means 17.

  FIG. 7B shows a state in which the first structure 2 is being closed toward the apparatus main body 3. In this case, the engagement of the housing 12 is interlocked with the first structure 2 being closed. The stop piece 12b moves toward the raising piece 16b of the first holding means 16. When the first structure 2 is closed, the upper surface of the locking piece 12b of the housing 12 abuts against the bent piece 16a of the first holding means 16, but the second holding means 17 is connected to the operation portion 17b. When it is completely rotated to a predetermined position by operating (see FIG. 4), the pressing piece 30c of the first holding means 30 is moved to the position shown in FIG. ), The first holding means 30 rotates clockwise in FIG. 7B. As a result, even if the locking piece 12b of the housing 12 is lifted, it is pushed down by the lower surface of the bent piece 30a and displaced and positioned in the state shown in FIG.

  When the first structure 2 is opened in a direction away from the apparatus main body 3, the second holding means 17 is operated by the operator to operate the operation portion 17 b so that the claw portion 17 a is projected from the engagement member 21. Separated from 21a. As a result, the leading end of the claw portion of the second holding means 17 abuts on the push-back piece 30d of the first holding means 30, and the first holding means 30 is rotated counterclockwise in FIG. . When the first holding means 30 rotates counterclockwise, the bent piece 30a is detached from the locking piece 12b of the housing 12, so that the housing 12 can be opened.

  According to the embodiment described above, the engagement of the housing 12 by the first holding means 30 can be achieved only by setting a relationship in which a part of the first holding means 30 and the second holding means 17 are engaged with each other. Even if the pressing action on the stop piece 12b is insufficient, the second holding means 17 can make the pressing action of the locking piece 12b sufficient, so that the fixing device 11 can be positioned reliably.

It is a figure which shows the image forming apparatus provided with the 1st, 2nd structure used as the premise structure to which the Example of this invention is applied. FIG. 2 is a diagram illustrating an open state of a structure in the image forming apparatus illustrated in FIG. 1. FIG. 2 is a perspective view for explaining a configuration of a holding mechanism used in the structure of the image forming apparatus shown in FIG. 1. It is a figure explaining the operation part of the 2nd holding means used for the holding mechanism shown in FIG. 3A and 3B are arrow views in the direction indicated by a symbol K, where FIG. 3A illustrates a state in which one of the structures is closed, and FIG. 3B illustrates a state in which one of the structures is closed. It is a figure which shows the state in the middle of closing one of the structures used for the principal part structure shown in FIG. 1A and 1B are diagrams illustrating a configuration of a main part of an image forming apparatus according to an embodiment of the present invention, in which FIG. 1A illustrates a state in which one of the structures is closed, and FIG. .

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Copier which is one of the image forming apparatuses 2 One of the structures 3 The apparatus main body forming the other of the structures 4 Photosensitive drum 8 Transfer device 11 Fixing device 12 Housing 12b Locking piece 13 Heating roller 14 Pressure roller 16, 30 1st holding means 17 2nd holding means 17a Claw part 17b Operation part 20 Swing support shaft for 2nd holding means 30c Pressing piece 30d Pushing back piece

Claims (3)

A fixing device having a pair of rollers forming a conveying member is disposed on a first structure that includes first and second structures divided into two and is supported by the second structure so as to be freely opened and closed. In the image forming apparatus having the configuration as described above,
A first holding means provided so as to be rotatable with respect to the second structure and capable of locking the first structure when the first structure is closed;
Provided rotatably with respect to the first structure and a matable second holding means to the second structure when the first structure is closed,
The first holding means is pressed by the second holding means when a pressing portion provided at a part thereof so as to face the second holding means is closed with the first structure. Accordingly, the first structure body is configured to be rotated in the locking direction, and the second holding means is interlocked with the second structure body when the fitting with the second structure body is released. The image forming apparatus is configured to be rotated in a direction to release the locking of the first structure. The image forming apparatus according to claim 1.
The first holding means is provided in the second structure body in correspondence with an opening / closing end side having a large radius from the opening / closing fulcrum in the first structure body, and the second holding means is provided in the first structure body. An image forming apparatus, wherein the first structure is provided corresponding to an opening / closing base end having a small radius from the opening / closing fulcrum in the structure. The image forming apparatus according to claim 1.
The second holding means is provided with a fitting portion with respect to the second structure in the longitudinal direction first about the swinging support shaft, and an operation portion rotated by the operator in the other longitudinal direction,
The first holding means is separate from the locking portion for the first structure in a direction in which the locking portion with the first structure is locked by the fitting portion of the second holding means. A pressing portion to be pressed and a push-back portion to be pushed back in a direction opposite to the locking direction are provided, and the fitting portion in the second holding means acts on either the pressing portion or the push-back portion. An image forming apparatus, wherein the first structure is locked and unlocked.

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